18... e8g8  19. c3c4 Carlsen takes the chance to modify the pawn structure to \"hanging pawns.\" From the isolani family, this is considered the most beneficial relative. 19... a3e7 Once again solid and good. The bishop is moving out of the opponent's attack to a better square, protecting the kingside in the process. 20. h2h4 White's play is related to a kingside attack, and this move secures the g5-point for the white pieces. 20... f8d8 